panic: m_copym0: short mbuf chain Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *328332 65520 0 0x12 0 0 sshd db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cb89c) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053e22b00,3ac,2ec,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac9328,9,fffffd8053e22a00,0,0,ffff80001d7a7280) at tcp_usrreq+0xa54 sosend(fffffd805dac9328,0,ffff80001d7aecf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7a7280,4,ffff80001d7aecf8,0,ffff80001d7aede0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7a7280,ffff80001d7aed90,ffff80001d7aede0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7aee60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe5bb0, count: 5 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs. ddb> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic m_copym0: short mbuf chain ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cb89c) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053e22b00,3ac,2ec,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac9328,9,fffffd8053e22a00,0,0,ffff80001d7a7280) at tcp_usrreq+0xa54 sosend(fffffd805dac9328,0,ffff80001d7aecf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7a7280,4,ffff80001d7aecf8,0,ffff80001d7aede0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7a7280,ffff80001d7aed90,ffff80001d7aede0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7aee60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe5bb0, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80001d7ae7c0 rbx 0xffff80001d7ae870 rdx 0x2 rcx 0 rax 0x1 r8 0xffffffff81d602ef kprintf+0x15f r9 0x1 r10 0x2 r11 0x8edf40f528a81b3f r12 0x3000000008 r13 0xffff80001d7ae7d0 r14 0x100 r15 0x1 rip 0xffffffff82006a18 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d7ae7b0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (sshd) pid=328332 stat=onproc flags process=12 proc=0 pri=24, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff80001d7a8390,0xffff80001d7a7770 process=0xffff8000ffff8e78 user=0xffff80001d7a9000, vmspace=0xfffffd806bc0a880 estcpu=0, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 36486 56145 8468 0 2 0x2 syz-executor.0 56063 384016 0 0 3 0x14280 nfsidl nfsio 14452 155931 0 0 3 0x14280 nfsidl nfsio 96805 83962 0 0 3 0x14280 nfsidl nfsio 62170 336537 0 0 3 0x14280 nfsidl nfsio 21297 112510 0 0 3 0x14280 nfsidl nfsio 60490 237655 0 0 3 0x14280 nfsidl nfsio 88829 308817 0 0 3 0x14280 nfsidl nfsio 66021 270534 0 0 3 0x14280 nfsidl nfsio 84383 105043 0 0 3 0x14280 nfsidl nfsio 39405 396900 0 0 3 0x14280 nfsidl nfsio 13029 464797 0 0 3 0x14280 nfsidl nfsio 5913 58101 0 0 3 0x14280 nfsidl nfsio 3488 135286 0 0 3 0x14280 nfsidl nfsio 66205 484861 0 0 3 0x14280 nfsidl nfsio 84052 334089 0 0 3 0x14280 nfsidl nfsio 95265 96541 0 0 3 0x14280 nfsidl nfsio 77706 140113 0 0 3 0x14280 nfsidl nfsio 36004 296093 0 0 3 0x14280 nfsidl nfsio 17136 99574 0 0 3 0x14280 nfsidl nfsio 82048 77223 0 0 3 0x14280 nfsidl nfsio 60347 68725 0 0 3 0x14200 bored sosplice 43207 34209 0 0 3 0x14200 acct acct 51682 222457 8468 0 3 0x82 nanosleep syz-executor.1 8468 141793 42919 0 3 0x82 thrsleep syz-fuzzer 8468 121406 42919 0 2 0x4000002 syz-fuzzer 8468 315717 42919 0 3 0x4000082 thrsleep syz-fuzzer 8468 260129 42919 0 3 0x4000082 thrsleep syz-fuzzer 8468 204592 42919 0 3 0x4000082 thrsleep syz-fuzzer 8468 470271 42919 0 2 0x4000002 syz-fuzzer 8468 290780 42919 0 3 0x4000082 thrsleep syz-fuzzer 8468 203841 42919 0 3 0x4000082 thrsleep syz-fuzzer 42919 498337 65520 0 3 0x10008a pause ksh *65520 328332 64677 0 7 0x12 sshd 45579 12487 1 0 3 0x100083 ttyin getty 64677 191649 1 0 3 0x80 select sshd 81643 295266 59580 73 3 0x100090 kqread syslogd 59580 187490 1 0 3 0x100082 netio syslogd 14930 299688 1 77 3 0x100090 poll dhclient 73864 176797 1 0 3 0x80 poll dhclient 75820 296952 0 0 3 0x14200 bored smr 52355 299507 0 0 3 0x14200 pgzero zerothread 68815 383986 0 0 3 0x14200 aiodoned aiodoned 29910 404563 0 0 3 0x14200 syncer update 63011 402487 0 0 3 0x14200 cleaner cleaner 70663 429118 0 0 3 0x14200 reaper reaper 52875 214374 0 0 3 0x14200 pgdaemon pagedaemon 65188 410905 0 0 3 0x14200 bored crynlk 12809 322361 0 0 3 0x14200 bored crypto 80377 277373 0 0 3 0x40014200 acpi0 acpi0 44627 288633 0 0 3 0x14200 bored softnet 85433 92799 0 0 3 0x14200 bored systqmp 87479 381871 0 0 3 0x14200 bored systq 36502 260130 0 0 3 0x40014200 bored softclock 53978 341196 0 0 3 0x40014200 idle0 1 27789 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb> show all locks No such command ddb> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9513 6351K 14530K 78643K 11688 0 pcb 13 8K 8K 78643K 181 0 rtable 99 3K 4K 78643K 569 0 ifaddr 87 17K 18K 78643K 254 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 16K 78643K 48 0 ioctlops 0 0K 2K 78643K 102 0 iov 0 0K 16K 78643K 148 0 mount 1 1K 1K 78643K 1 0 vnodes 1212 76K 77K 78643K 1660 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 7 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 199 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1809 195K 288K 78643K 12938 0 file desc 4 9K 25K 78643K 857 0 sigio 0 0K 0K 78643K 22 0 proc 51 38K 63K 78643K 562 0 subproc 32 2K 2K 78643K 85 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 99 0 in_multi 98 4K 4K 78643K 214 0 ether_multi 1 0K 0K 78643K 30 0 mrt 0 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 55 254K 254K 78643K 55 0 exec 0 0K 1K 78643K 297 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 7 26K 26K 78643K 7 0 UVM amap 145 137K 137K 78643K 2899 0 UVM aobj 47 6K 6K 78643K 51 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 1K 78643K 2060 0 NDP 13 0K 0K 78643K 50 0 temp 136 3042K 3115K 78643K 13751 0 kqueue 3 4K 20K 78643K 48 0 SYN cache 2 16K 16K 78643K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 16 0 9 1 0 1 1 0 8 0 rtpcb 80 53 0 51 1 0 1 1 0 8 0 rtentry 112 94 0 56 2 0 2 2 0 8 0 unpcb 120 423 0 415 1 0 1 1 0 8 0 syncache 264 13 0 13 3 3 0 1 0 8 0 tcpqe 32 10 0 10 1 1 0 1 0 8 0 tcpcb 544 1449 0 1445 2 1 1 2 0 8 0 ipq 40 1 0 1 1 1 0 1 0 8 0 ipqe 40 2 0 2 1 1 0 1 0 8 0 inpcb 280 3155 0 3146 4 2 2 2 0 8 0 nd6 48 18 0 12 1 0 1 1 0 8 0 pkpcb 40 4 0 4 1 1 0 1 0 8 0 swfcl 56 2 0 0 1 0 1 1 0 8 0 ppxss 1128 1 0 1 1 1 0 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 453 0 255 15 2 13 13 0 8 0 art_table 32 455 0 255 2 0 2 2 0 8 0 art_node 16 93 0 61 1 0 1 1 0 8 0 sysvmsgpl 40 44 0 20 1 0 1 1 0 8 0 semapl 112 197 0 187 1 0 1 1 0 8 0 shmpl 112 49 0 4 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2578 0 1185 88 0 88 88 0 8 0 ffsino 240 2578 0 1185 83 0 83 83 0 8 0 nchpl 144 3904 0 2313 60 0 60 60 0 8 0 uvmvnodes 72 2907 0 0 53 0 53 53 0 8 0 vnodes 208 2907 0 0 153 0 153 153 0 8 0 namei 1024 11108 0 11108 3 2 1 1 0 8 1 vcpupl 1984 16 0 0 2 0 2 2 0 8 0 vmpool 528 26 0 10 3 1 2 2 0 8 0 scsiplug 64 1 0 1 1 1 0 1 0 8 0 scxspl 192 11347 0 11347 1 0 1 1 0 8 1 plimitpl 152 103 0 96 1 0 1 1 0 8 0 sigapl 424 1056 0 1007 6 0 6 6 0 8 0 futexpl 56 19887 0 19887 3 2 1 1 0 8 1 knotepl 112 148 0 129 1 0 1 1 0 8 0 kqueuepl 144 122 0 120 1 0 1 1 0 8 0 pipelkpl 16 188 0 178 1 0 1 1 0 8 0 pipepl 120 376 0 357 2 1 1 2 0 8 0 fdescpl 432 1020 0 1007 2 0 2 2 0 8 0 filepl 120 7791 0 7696 4 0 4 4 0 8 1 lockfpl 104 161 0 160 1 0 1 1 0 8 0 lockfspl 48 56 0 55 1 0 1 1 0 8 0 sessionpl 112 20 0 10 1 0 1 1 0 8 0 pgrppl 48 26 0 16 1 0 1 1 0 8 0 ucredpl 96 814 0 807 1 0 1 1 0 8 0 zombiepl 144 1007 0 1006 1 0 1 1 0 8 0 processpl 920 1056 0 1006 7 0 7 7 0 8 0 procpl 624 2049 0 1992 5 0 5 5 0 8 0 sosppl 128 13 0 13 4 4 0 1 0 8 0 sockpl 400 3640 0 3620 8 5 3 5 0 8 0 mcl64k 65536 100 0 100 3 2 1 1 0 8 1 mcl16k 16384 3 0 3 2 2 0 1 0 8 0 mcl12k 12288 35 0 35 4 3 1 1 0 8 1 mcl9k 9216 16 0 16 4 3 1 1 0 8 1 mcl8k 8192 20 0 20 3 3 0 1 0 8 0 mcl4k 4096 87 0 87 4 3 1 1 0 8 1 mcl2k2 2112 5 0 5 4 4 0 1 0 8 0 mcl2k 2048 71071 0 71030 13 7 6 11 0 8 0 mtagpl 80 59 0 25 2 1 1 1 0 8 0 mbufpl 256 119491 0 119314 19 7 12 13 0 8 0 bufpl 280 4968 0 129 346 0 346 346 0 8 0 anonpl 16 116909 0 102112 107 37 70 77 0 107 8 amapchunkpl 152 5301 0 5157 28 21 7 20 0 158 0 amappl16 192 5119 0 4289 73 28 45 54 0 8 3 amappl15 184 3 0 1 1 0 1 1 0 8 0 amappl14 176 521 0 513 1 0 1 1 0 8 0 amappl13 168 145 0 141 1 0 1 1 0 8 0 amappl12 160 112 0 109 1 0 1 1 0 8 0 amappl11 152 209 0 200 1 0 1 1 0 8 0 amappl10 144 57 0 53 1 0 1 1 0 8 0 amappl9 136 380 0 378 1 0 1 1 0 8 0 amappl8 128 400 0 358 2 0 2 2 0 8 0 amappl7 120 164 0 151 1 0 1 1 0 8 0 amappl6 112 184 0 177 1 0 1 1 0 8 0 amappl5 104 842 0 832 1 0 1 1 0 8 0 amappl4 96 655 0 627 1 0 1 1 0 8 0 amappl3 88 641 0 634 1 0 1 1 0 8 0 amappl2 80 7126 0 7069 2 0 2 2 0 8 0 amappl1 72 27565 0 27168 23 13 10 17 0 8 0 amappl 80 2316 0 2269 2 0 2 2 0 84 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 64 50 0 4 1 0 1 1 0 8 0 uaddrrnd 24 1046 0 1017 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1046 0 1017 1 0 1 1 0 8 0 vmmpekpl 168 10053 0 10011 3 1 2 3 0 8 0 vmmpepl 168 126914 0 125068 145 53 92 116 0 357 2 vmsppl 272 1045 0 1017 4 1 3 3 0 8 1 pdppl 4096 2098 0 2050 8 1 7 7 0 8 0 pvpl 32 323938 0 306379 215 42 173 183 0 265 27 pmappl 200 1045 0 1017 2 0 2 2 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 267 0 38 7 0 7 7 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cb89c) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053e22b00,3ac,2ec,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac9328,9,fffffd8053e22a00,0,0,ffff80001d7a7280) at tcp_usrreq+0xa54 sosend(fffffd805dac9328,0,ffff80001d7aecf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7a7280,4,ffff80001d7aecf8,0,ffff80001d7aede0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7a7280,ffff80001d7aed90,ffff80001d7aede0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7aee60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe5bb0, count: -10 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821cb89c) at panic+0x15c sys/kern/subr_prf.c:207 m_copym(fffffd8053e22b00,3ac,2ec,2) at m_copym+0x553 sys/kern/uipc_mbuf.c:695 tcp_output(ffff8000009f5100) at tcp_output+0x154d sys/netinet/tcp_output.c:673 tcp_usrreq(fffffd805dac9328,9,fffffd8053e22a00,0,0,ffff80001d7a7280) at tcp_usrreq+0xa54 sosend(fffffd805dac9328,0,ffff80001d7aecf8,0,0,80) at sosend+0x669 sys/kern/uipc_socket.c:549 dofilewritev(ffff80001d7a7280,4,ffff80001d7aecf8,0,ffff80001d7aede0) at dofilewritev+0x1ab sys/kern/sys_generic.c:365 sys_write(ffff80001d7a7280,ffff80001d7aed90,ffff80001d7aede0) at sys_write+0x83 sys/kern/sys_generic.c:285 syscall(ffff80001d7aee60) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe5bb0, count: -10